If Theresa May had been a luckier politician she might have faced an easier challenge on her first day back at Westminster: solving world hunger perhaps, persuading the Taliban to take up knitting or smuggling Tony Blair into Waterstone's.

Instead the home secretary got a big, black binliner full of stinking political rubbish dumped into her lap, the kind of raw material that News of the World reporters tiptoe away with from the dustbins of their victims.

Except that in this case the investigators were outraged opposition MPs and the targets under surveillance were Scotland Yard, the News of the Screws itself and Andy Coulson, the boss's pet rottweiler, all mixed up in the phone-hacking affair. A Lib Dem cabinet minister even called for Coulson to be sacked.

It was a situation where even May could see that a careless word could end a woman's career in its sub-prime. So she stuck to the autocue, praying for her nightmare to end so she could get back to immigration, alcoholism and genital mutilation.

It did end, but only after 30 excruciating minutes which culminated in one Labour MP, Madeleine Moon, calling the controversy "the British Watergate" (someone had to) while another, Chris Bryant, asked the Speaker to check how many MPs' phones had been hacked – because the home secretary wouldn't. Humiliation! Shame! Thoroughly deserved!

All May would say – repeatedly – was that it is not her job to interfere with operational police matters. The royal affair had been investigated, two men had been jailed, assorted reviews had concluded that all was well, but the Met police would look at new evidence, if any, about its own investigative failings. The Vatican's paedophile investigation unit could not have put it better. "If you have any complaints, children, you must bring your evidence to Father O'Grope."

After weeks of privation MPs weren't going to pass up a chance to be pompous again. It is no fun being on holiday, having to say "On a point of order, Mr Whippy, may I have two choc ices and a can of Irn-Bru" or " May I warn the hon gentleman that if the Ryanair flight to Corfu does not take off shortly I will be tabling a question to the prime minister".

But this was the real thing. So Labour's Tom Watson, a man whose bins have been done over by the tabloids, delivered one of the best made-for-TV-news soundbites in months: six terse points that badly dented the coalition's defence and ended with a magnificently pompous bit about "the integrity of our democracy being under scrutiny around the world". Yeah, right.

Watson's points were solid enough to put Tory MPs to the test. Most of them, obtuse to the point of mendacity, failed, though John Whittingdale, chairman of the media select committee bravely hinted at disquiet. Lib Dem backbenchers were more sceptical and their cabinet colleague, Chris Huhne, was brilliant.

Coulson was either in charge of the News of the World when it was out of control or in charge of the racket. If Gordon Brown was right to sack his spin troll, Damian McBride, was not David Cameron right to sack Coulson, thundered Huhne. Admittedly, this was last year, but Alan Johnson helpfully dug the quotes out.

Johnson's revenge was caustic. Taunted with inaction before polling day he told May: "When I was home secretary dealing with this case, there was nobody anywhere in government who was implicated. Now there is. You and the deputy prime minister have lectured the house many times about your perception of the surveillance state created by the previous government. It appears that you may have your very own expert on the matter in charge of government communications."

Ouch! It couldn't get much worse than that, could it? Yes. Next up was Nick Clegg defending his voting reforms bill against attacks from all sides. Even the bright spark who suggested bringing MPs back a month early must have realised his mistake by now. But Andy Coulson knew nothing about it.